using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Web;

namespace SKIT.FlurlHttpClient
{
    /// <summary>
    /// SKIT.FlurlHttpClient 常量集之 MIME 类型。
    /// </summary>
    public static partial class MimeTypes
    {
        public const string Text = "text/plain";

        public const string Xml = "application/xml";

        public const string Json = "application/json";

        public const string FormUrlEncoded = "application/x-www-form-urlencoded";

        public const string FormData = "multipart/form-data";

        public const string Binary = "application/octet-stream";
    }

    partial class MimeTypes
    {
#if NETFRAMEWORK
        /// <summary>
        /// 返回指定文件名的 MIME 映射。
        /// </summary>
        /// <param name="fileName"></param>
        /// <returns></returns>
        public static string? GetMimeMapping(string fileName)
        {
            return (fileName is null) ? Binary : MimeMapping.GetMimeMapping(fileName);
        }
#else
        private static Lazy<IDictionary<string, string>> _mappings = new Lazy<IDictionary<string, string>>(() =>
        {
            IDictionary<string, string> dict = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
            {
                /**
                 * From
                 *   %UserProfile%\Documents\IISExpress\config\applicationHost.config
                 *   %ProgramFiles%\IIS Express\AppServer\applicationHost.config
                 */
                { ".323", "text/h323"},
                { ".3g2", "video/3gpp2"},
                { ".3gp", "video/3gpp"},
                { ".3gp2", "video/3gpp2"},
                { ".3gpp", "video/3gpp"},
                { ".7z", "application/x-7z-compressed"},
                { ".aa", "audio/audible"},
                { ".AAC", "audio/aac"},
                { ".aaf", "application/octet-stream"},
                { ".aax", "audio/vnd.audible.aax"},
                { ".ac3", "audio/ac3"},
                { ".aca", "application/octet-stream"},
                { ".accda", "application/msaccess.addin"},
                { ".accdb", "application/msaccess"},
                { ".accdc", "application/msaccess.cab"},
                { ".accde", "application/msaccess"},
                { ".accdr", "application/msaccess.runtime"},
                { ".accdt", "application/msaccess"},
                { ".accdw", "application/msaccess.webapplication"},
                { ".accft", "application/msaccess.ftemplate"},
                { ".acx", "application/internet-property-stream"},
                { ".AddIn", "text/xml"},
                { ".ade", "application/msaccess"},
                { ".adobebridge", "application/x-bridge-url"},
                { ".adp", "application/msaccess"},
                { ".ADT", "audio/vnd.dlna.adts"},
                { ".ADTS", "audio/aac"},
                { ".afm", "application/octet-stream"},
                { ".ai", "application/postscript"},
                { ".aif", "audio/x-aiff"},
                { ".aifc", "audio/aiff"},
                { ".aiff", "audio/aiff"},
                { ".air", "application/vnd.adobe.air-application-installer-package+zip"},
                { ".amc", "application/x-mpeg"},
                { ".application", "application/x-ms-application"},
                { ".art", "image/x-jg"},
                { ".asa", "application/xml"},
                { ".asax", "application/xml"},
                { ".ascx", "application/xml"},
                { ".asd", "application/octet-stream"},
                { ".asf", "video/x-ms-asf"},
                { ".ashx", "application/xml"},
                { ".asi", "application/octet-stream"},
                { ".asm", "text/plain"},
                { ".asmx", "application/xml"},
                { ".aspx", "application/xml"},
                { ".asr", "video/x-ms-asf"},
                { ".asx", "video/x-ms-asf"},
                { ".atom", "application/atom+xml"},
                { ".au", "audio/basic"},
                { ".avi", "video/x-msvideo"},
                { ".axs", "application/olescript"},
                { ".bas", "text/plain"},
                { ".bcpio", "application/x-bcpio"},
                { ".bin", "application/octet-stream"},
                { ".bmp", "image/bmp"},
                { ".c", "text/plain"},
                { ".cab", "application/octet-stream"},
                { ".caf", "audio/x-caf"},
                { ".calx", "application/vnd.ms-office.calx"},
                { ".cat", "application/vnd.ms-pki.seccat"},
                { ".cc", "text/plain"},
                { ".cd", "text/plain"},
                { ".cdda", "audio/aiff"},
                { ".cdf", "application/x-cdf"},
                { ".cer", "application/x-x509-ca-cert"},
                { ".chm", "application/octet-stream"},
                { ".class", "application/x-java-applet"},
                { ".clp", "application/x-msclip"},
                { ".cmx", "image/x-cmx"},
                { ".cnf", "text/plain"},
                { ".cod", "image/cis-cod"},
                { ".config", "application/xml"},
                { ".contact", "text/x-ms-contact"},
                { ".coverage", "application/xml"},
                { ".cpio", "application/x-cpio"},
                { ".cpp", "text/plain"},
                { ".crd", "application/x-mscardfile"},
                { ".crl", "application/pkix-crl"},
                { ".crt", "application/x-x509-ca-cert"},
                { ".cs", "text/plain"},
                { ".csdproj", "text/plain"},
                { ".csh", "application/x-csh"},
                { ".csproj", "text/plain"},
                { ".css", "text/css"},
                { ".csv", "text/csv"},
                { ".cur", "application/octet-stream"},
                { ".cxx", "text/plain"},
                { ".dat", "application/octet-stream"},
                { ".datasource", "application/xml"},
                { ".dbproj", "text/plain"},
                { ".dcr", "application/x-director"},
                { ".def", "text/plain"},
                { ".deploy", "application/octet-stream"},
                { ".der", "application/x-x509-ca-cert"},
                { ".dgml", "application/xml"},
                { ".dib", "image/bmp"},
                { ".dif", "video/x-dv"},
                { ".dir", "application/x-director"},
                { ".disco", "text/xml"},
                { ".dll", "application/x-msdownload"},
                { ".dll.config", "text/xml"},
                { ".dlm", "text/dlm"},
                { ".doc", "application/msword"},
                { ".docm", "application/vnd.ms-word.document.macroEnabled.12"},
                { ".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
                { ".dot", "application/msword"},
                { ".dotm", "application/vnd.ms-word.template.macroEnabled.12"},
                { ".dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template"},
                { ".dsp", "application/octet-stream"},
                { ".dsw", "text/plain"},
                { ".dtd", "text/xml"},
                { ".dtsConfig", "text/xml"},
                { ".dv", "video/x-dv"},
                { ".dvi", "application/x-dvi"},
                { ".dwf", "drawing/x-dwf"},
                { ".dwp", "application/octet-stream"},
                { ".dxr", "application/x-director"},
                { ".eml", "message/rfc822"},
                { ".emz", "application/octet-stream"},
                { ".eot", "application/octet-stream"},
                { ".eps", "application/postscript"},
                { ".etl", "application/etl"},
                { ".etx", "text/x-setext"},
                { ".evy", "application/envoy"},
                { ".exe", "application/octet-stream"},
                { ".exe.config", "text/xml"},
                { ".fdf", "application/vnd.fdf"},
                { ".fif", "application/fractals"},
                { ".filters", "Application/xml"},
                { ".fla", "application/octet-stream"},
                { ".flr", "x-world/x-vrml"},
                { ".flv", "video/x-flv"},
                { ".fsscript", "application/fsharp-script"},
                { ".fsx", "application/fsharp-script"},
                { ".generictest", "application/xml"},
                { ".gif", "image/gif"},
                { ".group", "text/x-ms-group"},
                { ".gsm", "audio/x-gsm"},
                { ".gtar", "application/x-gtar"},
                { ".gz", "application/x-gzip"},
                { ".h", "text/plain"},
                { ".hdf", "application/x-hdf"},
                { ".hdml", "text/x-hdml"},
                { ".hhc", "application/x-oleobject"},
                { ".hhk", "application/octet-stream"},
                { ".hhp", "application/octet-stream"},
                { ".hlp", "application/winhlp"},
                { ".hpp", "text/plain"},
                { ".hqx", "application/mac-binhex40"},
                { ".hta", "application/hta"},
                { ".htc", "text/x-component"},
                { ".htm", "text/html"},
                { ".html", "text/html"},
                { ".htt", "text/webviewhtml"},
                { ".hxa", "application/xml"},
                { ".hxc", "application/xml"},
                { ".hxd", "application/octet-stream"},
                { ".hxe", "application/xml"},
                { ".hxf", "application/xml"},
                { ".hxh", "application/octet-stream"},
                { ".hxi", "application/octet-stream"},
                { ".hxk", "application/xml"},
                { ".hxq", "application/octet-stream"},
                { ".hxr", "application/octet-stream"},
                { ".hxs", "application/octet-stream"},
                { ".hxt", "text/html"},
                { ".hxv", "application/xml"},
                { ".hxw", "application/octet-stream"},
                { ".hxx", "text/plain"},
                { ".i", "text/plain"},
                { ".ico", "image/x-icon"},
                { ".ics", "application/octet-stream"},
                { ".idl", "text/plain"},
                { ".ief", "image/ief"},
                { ".iii", "application/x-iphone"},
                { ".inc", "text/plain"},
                { ".inf", "application/octet-stream"},
                { ".inl", "text/plain"},
                { ".ins", "application/x-internet-signup"},
                { ".ipa", "application/x-itunes-ipa"},
                { ".ipg", "application/x-itunes-ipg"},
                { ".ipproj", "text/plain"},
                { ".ipsw", "application/x-itunes-ipsw"},
                { ".iqy", "text/x-ms-iqy"},
                { ".isp", "application/x-internet-signup"},
                { ".ite", "application/x-itunes-ite"},
                { ".itlp", "application/x-itunes-itlp"},
                { ".itms", "application/x-itunes-itms"},
                { ".itpc", "application/x-itunes-itpc"},
                { ".IVF", "video/x-ivf"},
                { ".jar", "application/java-archive"},
                { ".java", "application/octet-stream"},
                { ".jck", "application/liquidmotion"},
                { ".jcz", "application/liquidmotion"},
                { ".jfif", "image/pjpeg"},
                { ".jnlp", "application/x-java-jnlp-file"},
                { ".jpb", "application/octet-stream"},
                { ".jpe", "image/jpeg"},
                { ".jpeg", "image/jpeg"},
                { ".jpg", "image/jpeg"},
                { ".js", "application/x-javascript"},
                { ".jsx", "text/jscript"},
                { ".jsxbin", "text/plain"},
                { ".latex", "application/x-latex"},
                { ".library-ms", "application/windows-library+xml"},
                { ".lit", "application/x-ms-reader"},
                { ".loadtest", "application/xml"},
                { ".lpk", "application/octet-stream"},
                { ".lsf", "video/x-la-asf"},
                { ".lst", "text/plain"},
                { ".lsx", "video/x-la-asf"},
                { ".lzh", "application/octet-stream"},
                { ".m13", "application/x-msmediaview"},
                { ".m14", "application/x-msmediaview"},
                { ".m1v", "video/mpeg"},
                { ".m2t", "video/vnd.dlna.mpeg-tts"},
                { ".m2ts", "video/vnd.dlna.mpeg-tts"},
                { ".m2v", "video/mpeg"},
                { ".m3u", "audio/x-mpegurl"},
                { ".m3u8", "audio/x-mpegurl"},
                { ".m4a", "audio/m4a"},
                { ".m4b", "audio/m4b"},
                { ".m4p", "audio/m4p"},
                { ".m4r", "audio/x-m4r"},
                { ".m4v", "video/x-m4v"},
                { ".mac", "image/x-macpaint"},
                { ".mak", "text/plain"},
                { ".man", "application/x-troff-man"},
                { ".manifest", "application/x-ms-manifest"},
                { ".map", "text/plain"},
                { ".master", "application/xml"},
                { ".mda", "application/msaccess"},
                { ".mdb", "application/x-msaccess"},
                { ".mde", "application/msaccess"},
                { ".mdp", "application/octet-stream"},
                { ".me", "application/x-troff-me"},
                { ".mfp", "application/x-shockwave-flash"},
                { ".mht", "message/rfc822"},
                { ".mhtml", "message/rfc822"},
                { ".mid", "audio/mid"},
                { ".midi", "audio/mid"},
                { ".mix", "application/octet-stream"},
                { ".mk", "text/plain"},
                { ".mmf", "application/x-smaf"},
                { ".mno", "text/xml"},
                { ".mny", "application/x-msmoney"},
                { ".mod", "video/mpeg"},
                { ".mov", "video/quicktime"},
                { ".movie", "video/x-sgi-movie"},
                { ".mp2", "video/mpeg"},
                { ".mp2v", "video/mpeg"},
                { ".mp3", "audio/mpeg"},
                { ".mp4", "video/mp4"},
                { ".mp4v", "video/mp4"},
                { ".mpa", "video/mpeg"},
                { ".mpe", "video/mpeg"},
                { ".mpeg", "video/mpeg"},
                { ".mpf", "application/vnd.ms-mediapackage"},
                { ".mpg", "video/mpeg"},
                { ".mpp", "application/vnd.ms-project"},
                { ".mpv2", "video/mpeg"},
                { ".mqv", "video/quicktime"},
                { ".ms", "application/x-troff-ms"},
                { ".msi", "application/octet-stream"},
                { ".mso", "application/octet-stream"},
                { ".mts", "video/vnd.dlna.mpeg-tts"},
                { ".mtx", "application/xml"},
                { ".mvb", "application/x-msmediaview"},
                { ".mvc", "application/x-miva-compiled"},
                { ".mxp", "application/x-mmxp"},
                { ".nc", "application/x-netcdf"},
                { ".nsc", "video/x-ms-asf"},
                { ".nws", "message/rfc822"},
                { ".ocx", "application/octet-stream"},
                { ".oda", "application/oda"},
                { ".odc", "text/x-ms-odc"},
                { ".odh", "text/plain"},
                { ".odl", "text/plain"},
                { ".odp", "application/vnd.oasis.opendocument.presentation"},
                { ".ods", "application/oleobject"},
                { ".odt", "application/vnd.oasis.opendocument.text"},
                { ".one", "application/onenote"},
                { ".onea", "application/onenote"},
                { ".onepkg", "application/onenote"},
                { ".onetmp", "application/onenote"},
                { ".onetoc", "application/onenote"},
                { ".onetoc2", "application/onenote"},
                { ".orderedtest", "application/xml"},
                { ".osdx", "application/opensearchdescription+xml"},
                { ".p10", "application/pkcs10"},
                { ".p12", "application/x-pkcs12"},
                { ".p7b", "application/x-pkcs7-certificates"},
                { ".p7c", "application/pkcs7-mime"},
                { ".p7m", "application/pkcs7-mime"},
                { ".p7r", "application/x-pkcs7-certreqresp"},
                { ".p7s", "application/pkcs7-signature"},
                { ".pbm", "image/x-portable-bitmap"},
                { ".pcast", "application/x-podcast"},
                { ".pct", "image/pict"},
                { ".pcx", "application/octet-stream"},
                { ".pcz", "application/octet-stream"},
                { ".pdf", "application/pdf"},
                { ".pfb", "application/octet-stream"},
                { ".pfm", "application/octet-stream"},
                { ".pfx", "application/x-pkcs12"},
                { ".pgm", "image/x-portable-graymap"},
                { ".pic", "image/pict"},
                { ".pict", "image/pict"},
                { ".pkgdef", "text/plain"},
                { ".pkgundef", "text/plain"},
                { ".pko", "application/vnd.ms-pki.pko"},
                { ".pls", "audio/scpls"},
                { ".pma", "application/x-perfmon"},
                { ".pmc", "application/x-perfmon"},
                { ".pml", "application/x-perfmon"},
                { ".pmr", "application/x-perfmon"},
                { ".pmw", "application/x-perfmon"},
                { ".png", "image/png"},
                { ".pnm", "image/x-portable-anymap"},
                { ".pnt", "image/x-macpaint"},
                { ".pntg", "image/x-macpaint"},
                { ".pnz", "image/png"},
                { ".pot", "application/vnd.ms-powerpoint"},
                { ".potm", "application/vnd.ms-powerpoint.template.macroEnabled.12"},
                { ".potx", "application/vnd.openxmlformats-officedocument.presentationml.template"},
                { ".ppa", "application/vnd.ms-powerpoint"},
                { ".ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12"},
                { ".ppm", "image/x-portable-pixmap"},
                { ".pps", "application/vnd.ms-powerpoint"},
                { ".ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12"},
                { ".ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow"},
                { ".ppt", "application/vnd.ms-powerpoint"},
                { ".pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12"},
                { ".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
                { ".prf", "application/pics-rules"},
                { ".prm", "application/octet-stream"},
                { ".prx", "application/octet-stream"},
                { ".ps", "application/postscript"},
                { ".psc1", "application/PowerShell"},
                { ".psd", "application/octet-stream"},
                { ".psess", "application/xml"},
                { ".psm", "application/octet-stream"},
                { ".psp", "application/octet-stream"},
                { ".pub", "application/x-mspublisher"},
                { ".pwz", "application/vnd.ms-powerpoint"},
                { ".qht", "text/x-html-insertion"},
                { ".qhtm", "text/x-html-insertion"},
                { ".qt", "video/quicktime"},
                { ".qti", "image/x-quicktime"},
                { ".qtif", "image/x-quicktime"},
                { ".qtl", "application/x-quicktimeplayer"},
                { ".qxd", "application/octet-stream"},
                { ".ra", "audio/x-pn-realaudio"},
                { ".ram", "audio/x-pn-realaudio"},
                { ".rar", "application/octet-stream"},
                { ".ras", "image/x-cmu-raster"},
                { ".rat", "application/rat-file"},
                { ".rc", "text/plain"},
                { ".rc2", "text/plain"},
                { ".rct", "text/plain"},
                { ".rdlc", "application/xml"},
                { ".resx", "application/xml"},
                { ".rf", "image/vnd.rn-realflash"},
                { ".rgb", "image/x-rgb"},
                { ".rgs", "text/plain"},
                { ".rm", "application/vnd.rn-realmedia"},
                { ".rmi", "audio/mid"},
                { ".rmp", "application/vnd.rn-rn_music_package"},
                { ".roff", "application/x-troff"},
                { ".rpm", "audio/x-pn-realaudio-plugin"},
                { ".rqy", "text/x-ms-rqy"},
                { ".rtf", "application/rtf"},
                { ".rtx", "text/richtext"},
                { ".ruleset", "application/xml"},
                { ".s", "text/plain"},
                { ".safariextz", "application/x-safari-safariextz"},
                { ".scd", "application/x-msschedule"},
                { ".sct", "text/scriptlet"},
                { ".sd2", "audio/x-sd2"},
                { ".sdp", "application/sdp"},
                { ".sea", "application/octet-stream"},
                { ".searchConnector-ms", "application/windows-search-connector+xml"},
                { ".setpay", "application/set-payment-initiation"},
                { ".setreg", "application/set-registration-initiation"},
                { ".settings", "application/xml"},
                { ".sgimb", "application/x-sgimb"},
                { ".sgml", "text/sgml"},
                { ".sh", "application/x-sh"},
                { ".shar", "application/x-shar"},
                { ".shtml", "text/html"},
                { ".sit", "application/x-stuffit"},
                { ".sitemap", "application/xml"},
                { ".skin", "application/xml"},
                { ".sldm", "application/vnd.ms-powerpoint.slide.macroEnabled.12"},
                { ".sldx", "application/vnd.openxmlformats-officedocument.presentationml.slide"},
                { ".slk", "application/vnd.ms-excel"},
                { ".sln", "text/plain"},
                { ".slupkg-ms", "application/x-ms-license"},
                { ".smd", "audio/x-smd"},
                { ".smi", "application/octet-stream"},
                { ".smx", "audio/x-smd"},
                { ".smz", "audio/x-smd"},
                { ".snd", "audio/basic"},
                { ".snippet", "application/xml"},
                { ".snp", "application/octet-stream"},
                { ".sol", "text/plain"},
                { ".sor", "text/plain"},
                { ".spc", "application/x-pkcs7-certificates"},
                { ".spl", "application/futuresplash"},
                { ".src", "application/x-wais-source"},
                { ".srf", "text/plain"},
                { ".SSISDeploymentManifest", "text/xml"},
                { ".ssm", "application/streamingmedia"},
                { ".sst", "application/vnd.ms-pki.certstore"},
                { ".stl", "application/vnd.ms-pki.stl"},
                { ".sv4cpio", "application/x-sv4cpio"},
                { ".sv4crc", "application/x-sv4crc"},
                { ".svc", "application/xml"},
                { ".swf", "application/x-shockwave-flash"},
                { ".t", "application/x-troff"},
                { ".tar", "application/x-tar"},
                { ".tcl", "application/x-tcl"},
                { ".testrunconfig", "application/xml"},
                { ".testsettings", "application/xml"},
                { ".tex", "application/x-tex"},
                { ".texi", "application/x-texinfo"},
                { ".texinfo", "application/x-texinfo"},
                { ".tgz", "application/x-compressed"},
                { ".thmx", "application/vnd.ms-officetheme"},
                { ".thn", "application/octet-stream"},
                { ".tif", "image/tiff"},
                { ".tiff", "image/tiff"},
                { ".tlh", "text/plain"},
                { ".tli", "text/plain"},
                { ".toc", "application/octet-stream"},
                { ".tr", "application/x-troff"},
                { ".trm", "application/x-msterminal"},
                { ".trx", "application/xml"},
                { ".ts", "video/vnd.dlna.mpeg-tts"},
                { ".tsv", "text/tab-separated-values"},
                { ".ttf", "application/octet-stream"},
                { ".tts", "video/vnd.dlna.mpeg-tts"},
                { ".txt", "text/plain"},
                { ".u32", "application/octet-stream"},
                { ".uls", "text/iuls"},
                { ".user", "text/plain"},
                { ".ustar", "application/x-ustar"},
                { ".vb", "text/plain"},
                { ".vbdproj", "text/plain"},
                { ".vbk", "video/mpeg"},
                { ".vbproj", "text/plain"},
                { ".vbs", "text/vbscript"},
                { ".vcf", "text/x-vcard"},
                { ".vcproj", "Application/xml"},
                { ".vcs", "text/plain"},
                { ".vcxproj", "Application/xml"},
                { ".vddproj", "text/plain"},
                { ".vdp", "text/plain"},
                { ".vdproj", "text/plain"},
                { ".vdx", "application/vnd.ms-visio.viewer"},
                { ".vml", "text/xml"},
                { ".vscontent", "application/xml"},
                { ".vsct", "text/xml"},
                { ".vsd", "application/vnd.visio"},
                { ".vsi", "application/ms-vsi"},
                { ".vsix", "application/vsix"},
                { ".vsixlangpack", "text/xml"},
                { ".vsixmanifest", "text/xml"},
                { ".vsmdi", "application/xml"},
                { ".vspscc", "text/plain"},
                { ".vss", "application/vnd.visio"},
                { ".vsscc", "text/plain"},
                { ".vssettings", "text/xml"},
                { ".vssscc", "text/plain"},
                { ".vst", "application/vnd.visio"},
                { ".vstemplate", "text/xml"},
                { ".vsto", "application/x-ms-vsto"},
                { ".vsw", "application/vnd.visio"},
                { ".vsx", "application/vnd.visio"},
                { ".vtx", "application/vnd.visio"},
                { ".wav", "audio/wav"},
                { ".wave", "audio/wav"},
                { ".wax", "audio/x-ms-wax"},
                { ".wbk", "application/msword"},
                { ".wbmp", "image/vnd.wap.wbmp"},
                { ".wcm", "application/vnd.ms-works"},
                { ".wdb", "application/vnd.ms-works"},
                { ".wdp", "image/vnd.ms-photo"},
                { ".webarchive", "application/x-safari-webarchive"},
                { ".webtest", "application/xml"},
                { ".wiq", "application/xml"},
                { ".wiz", "application/msword"},
                { ".wks", "application/vnd.ms-works"},
                { ".WLMP", "application/wlmoviemaker"},
                { ".wlpginstall", "application/x-wlpg-detect"},
                { ".wlpginstall3", "application/x-wlpg3-detect"},
                { ".wm", "video/x-ms-wm"},
                { ".wma", "audio/x-ms-wma"},
                { ".wmd", "application/x-ms-wmd"},
                { ".wmf", "application/x-msmetafile"},
                { ".wml", "text/vnd.wap.wml"},
                { ".wmlc", "application/vnd.wap.wmlc"},
                { ".wmls", "text/vnd.wap.wmlscript"},
                { ".wmlsc", "application/vnd.wap.wmlscriptc"},
                { ".wmp", "video/x-ms-wmp"},
                { ".wmv", "video/x-ms-wmv"},
                { ".wmx", "video/x-ms-wmx"},
                { ".wmz", "application/x-ms-wmz"},
                { ".wpl", "application/vnd.ms-wpl"},
                { ".wps", "application/vnd.ms-works"},
                { ".wri", "application/x-mswrite"},
                { ".wrl", "x-world/x-vrml"},
                { ".wrz", "x-world/x-vrml"},
                { ".wsc", "text/scriptlet"},
                { ".wsdl", "text/xml"},
                { ".wvx", "video/x-ms-wvx"},
                { ".x", "application/directx"},
                { ".xaf", "x-world/x-vrml"},
                { ".xaml", "application/xaml+xml"},
                { ".xap", "application/x-silverlight-app"},
                { ".xbap", "application/x-ms-xbap"},
                { ".xbm", "image/x-xbitmap"},
                { ".xdr", "text/plain"},
                { ".xht", "application/xhtml+xml"},
                { ".xhtml", "application/xhtml+xml"},
                { ".xla", "application/vnd.ms-excel"},
                { ".xlam", "application/vnd.ms-excel.addin.macroEnabled.12"},
                { ".xlc", "application/vnd.ms-excel"},
                { ".xld", "application/vnd.ms-excel"},
                { ".xlk", "application/vnd.ms-excel"},
                { ".xll", "application/vnd.ms-excel"},
                { ".xlm", "application/vnd.ms-excel"},
                { ".xls", "application/vnd.ms-excel"},
                { ".xlsb", "application/vnd.ms-excel.sheet.binary.macroEnabled.12"},
                { ".xlsm", "application/vnd.ms-excel.sheet.macroEnabled.12"},
                { ".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
                { ".xlt", "application/vnd.ms-excel"},
                { ".xltm", "application/vnd.ms-excel.template.macroEnabled.12"},
                { ".xltx", "application/vnd.openxmlformats-officedocument.spreadsheetml.template"},
                { ".xlw", "application/vnd.ms-excel"},
                { ".xml", "text/xml"},
                { ".xmta", "application/xml"},
                { ".xof", "x-world/x-vrml"},
                { ".XOML", "text/plain"},
                { ".xpm", "image/x-xpixmap"},
                { ".xps", "application/vnd.ms-xpsdocument"},
                { ".xrm-ms", "text/xml"},
                { ".xsc", "application/xml"},
                { ".xsd", "text/xml"},
                { ".xsf", "text/xml"},
                { ".xsl", "text/xml"},
                { ".xslt", "text/xml"},
                { ".xsn", "application/octet-stream"},
                { ".xss", "application/xml"},
                { ".xtp", "application/octet-stream"},
                { ".xwd", "image/x-xwindowdump"},
                { ".z", "application/x-compress"},
                { ".zip", "application/x-zip-compressed"}
            };
            return new ReadOnlyDictionary<string, string>(dict);
        }, isThreadSafe: true);

        /// <summary>
        /// 返回指定文件名的 MIME 映射。
        /// </summary>
        /// <param name="fileName"></param>
        /// <returns></returns>
        public static string? GetMimeMapping(string fileName)
        {
            string? extension = Path.GetExtension(fileName);
            return extension is not null && _mappings.Value.TryGetValue(extension, out string? mimeType) ? mimeType: Binary;
        }
#endif
    }
}
